1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include <sys/types.h>
30#include <sys/errno.h>
31#include <sys/proc.h>
32#include <sys/procfs.h>
33#include <sys/sysmacros.h>
34#include <sys/uio.h>
35#include <sys/cmn_err.h>
36
37#if defined(__sparc)
38#include <sys/stack.h>
39#endif
40
41#define	STACK_BUF_SIZE	64	/* power of 2 */
42
43int
44prusrio(proc_t *p, enum uio_rw rw, struct uio *uiop, int old)
45{
46	/* longlong-aligned short buffer */
47	longlong_t buffer[STACK_BUF_SIZE / sizeof (longlong_t)];
48	int error = 0;
49	void *bp;
50	int allocated;
51	ssize_t total = uiop->uio_resid;
52	uintptr_t addr;
53	size_t len;
54
55	/* for short reads/writes, use the on-stack buffer */
56	if (uiop->uio_resid <= STACK_BUF_SIZE) {
57		bp = buffer;
58		allocated = 0;
59	} else {
60		bp = kmem_alloc(PAGESIZE, KM_SLEEP);
61		allocated = 1;
62	}
63
64#if defined(__sparc)
65	if (p == curproc)
66		(void) flush_user_windows_to_stack(NULL);
67#endif
68
69	switch (rw) {
70	case UIO_READ:
71		while (uiop->uio_resid != 0) {
72			addr = uiop->uio_offset;
73			len = MIN(uiop->uio_resid,
74			    PAGESIZE - (addr & PAGEOFFSET));
75
76			if ((error = uread(p, bp, len, addr)) != 0 ||
77			    (error = uiomove(bp, len, UIO_READ, uiop)) != 0)
78				break;
79		}
80
81		/*
82		 * ENXIO indicates that a page didn't exist. If the I/O was
83		 * truncated, return success; otherwise convert the error into
84		 * EIO. When obeying new /proc semantics, we don't return an
85		 * error for a read that begins at an invalid address.
86		 */
87		if (error == ENXIO) {
88			if (total != uiop->uio_resid || !old)
89				error = 0;
90			else
91				error = EIO;
92		}
93		break;
94	case UIO_WRITE:
95		while (uiop->uio_resid != 0) {
96			addr = uiop->uio_offset;
97			len = MIN(uiop->uio_resid,
98			    PAGESIZE - (addr & PAGEOFFSET));
99
100			if ((error = uiomove(bp, len, UIO_WRITE, uiop)) != 0)
101				break;
102			if ((error = uwrite(p, bp, len, addr)) != 0) {
103				uiop->uio_resid += len;
104				uiop->uio_loffset -= len;
105				break;
106			}
107		}
108
109		/*
110		 * ENXIO indicates that a page didn't exist. If the I/O was
111		 * truncated, return success; otherwise convert the error
112		 * into EIO.
113		 */
114		if (error == ENXIO) {
115			if (total != uiop->uio_resid)
116				error = 0;
117			else
118				error = EIO;
119		}
120		break;
121	default:
122		panic("prusrio: rw=%d neither UIO_READ not UIO_WRITE", rw);
123		/*NOTREACHED*/
124	}
125
126	if (allocated)
127		kmem_free(bp, PAGESIZE);
128
129	return (error);
130}
131